There are a number of companies that offer nuisance call programmes and they allow the recipient caller to make contact with callers even if the number is withheld. (Taxi companies often ring back and confirm bookings) This technology has been around for years, the emergency services have always had this facility. If this software is in use the 141 prefix does not make any difference.

bazzerfewi wrote on Jan 7^th, 2012 at 5:55pm:

Use of the 141 prefix (or a standing request for CLI to be withheld) compels your telephone company to mark the call so that your CLI is not provided to the person you are calling. If your telephone company fails to do this, or the other telephone company reveals the CLI when marked in this way, other than to a proper authority (e.g. the emergency services), this is a serious breach of data protection regulations.

Having had some extensive involvement in the issue of nuisance calls, I have never heard of anything such as the facility described above. I suspect that there is some misunderstanding in here somewhere.

Many are unaware that the general area from which you are calling (not your actual number) is provided to the telephone company which terminates the call. Some use this information to channel calls, or detect that one is not calling from overseas. This information is not deemed to be personal and so it cannot be withheld.


My view is that one should offer CLI if happy for the person called to call back on the number being used. It should be withheld if this is not the case. If a business would rather you called back on a different number, then it  can use a "presentation number" as the CLI. I argue strongly that those who are unable or unwilling to accept a return call should withhold their CLI. Sadly, there are many people who do not treat CLI in this simple manner.

There are serious issues around the misuse of published telephone directory information and the integrity of the ex-directory arrangements. We are also aware of problems with the security of remotely accessible voicemail systems. These lead many to withhold their CLI in circumstances other than those described above. This is an absolute right, which is established in legislation, with which all telephone companies must comply. Errors may occur, but I am not aware of any telephone company that is known to be commonly in breach.

Just found out the other day that despite my mums landline being ex-directory and CLI automatically withheld, when she rings the local taxi company, she now gets an automated message telling her the taxi is on its way.  Then, obviously, the taxi then arrives.

There are two problems I see here:

1. The CLI withheld 'flag' is obviously being ignored.
2. They know my mums address from the landline number.

With regards to '2', I can imagine before they introduced this services, they had on record my mums number (presumably always been ignoring the 'withheld' flag) and presumably they linked that to her address when she asked for a taxi from home.

With regards to '1', I think there are privacy issues here.  What's the point in automatically withholding or even manually withholding your number, if they (company called) can choose to bypass this?

With the exception of the emergency services (as mentioned by SCV), I don't believe anyone else should have this facility without a good reason.

Has anyone experienced this when ringing a taxi firm (or any company for that matter)?

The bit I'm concerned with is with the fact that they have your number regardless of whether withheld.

What's the point of having the facility to withhold your number if anyone can just ignore it and receive it anyhow?

bbb_uk wrote on Apr 24^th, 2012 at 4:48pm:

But the facility is with the provider of the person you are calling.

The caller's provider merely passes on to the receiver's provider, the request not to divulge the number. Thus, if the number is given out regardless, it is the receiver's provider that has done so, ignoring the request by the caller's provider not to give it out.

Dave wrote on Apr 24^th, 2012 at 6:06pm:
I know but obviously there is a breakdown of privacy somewhere along the line - obviously the TCP is choosing to ignore any 'withheld' request and doing so without good reason IMHO.

I also tried a call into OFCOM, the woman there was adamant that this cant happen and that if the number is being passed on to anyone it should be taken up with the Telco.

Is OFCOM unaware of developments in the industry over which it is supposed to regulate? 

I just checked Cordic up on the web, this is an American software package. Given that it has to have some connection with the telephone network to function is that use legal in the UK? ISTR BT being very stringent about what can be plugged in, surely this has to be able to interrogate the network to some extend to gain the "withheld" number". interesting...

Although being OFCOM that shouldn't surprise me...